That 1861 in the pictures linked by RSVP2RIP look a lot like an 1863. Do you know what the differences are?
I was curious about this myself, having just purchased a Remington clone. I knew that these were really the 1863 model but were refered to as the 1858 New Army, and I anxiously awaited a reply from the experts here on the forum. When an adequate answer was not forthcoming, I did a little research myself, and this is what I came up with. I must caution that I am not a Remington expert, simply a researcher, and anyone who knows more about this should certainly correct me if/when I go astray, but this is what I managed to come up with:
According to my sources, in 1856 the Remington company formed a partnership (among others) with Fordyce Beals, a professional firearms designer, in order to expand the company into the civilian firearms market. They were successful with a variety of small calibre pocket pistols, and Beals designed three spur triggered .31 cal. pocket revolvers, the third model utilizing a specially designed loading lever that held the cylinder pin in place.
Then, on September 14th 1858, Beals patented a six shot .36 cal. Navy style revolver based on the third model pocket pistol which used the same lever configuration - this is where the "1858" date comes in. The revolver looks very much like it's later incarnations, the major differences being a dove-tailed cone front sight, no safety notches, a 7 1/2" barrel and the loading lever is not "webbed", but is more squared off towards the pivot and looks similar to a Colt lever. In fact, the gun looks kind of like a Rogers and Spencer. Also, the frame does not have the cut out that exposes the barrel threads as in later models. These carried the mark " BEALS' PATENT. SEPT. 14. 1858 MANUFACTURED BY REMINGTONS' ILION. N.Y.".
The Army liked the pistol but wanted it in a .44 cal. version, which Remington produced. It retained the 1858 patent date, but had an 8" barrel and more of a web on the loading lever. The barrel threads were still shrouded, and there were still no safety notches on the cylinder between the nipples. Several thousands of these along with the Navy versions were sold to the Army for the price of $12 apiece.
Then, on Dec 17, 1861, William Elliot, a former dentist turned gun maker who had colaborated with Remington on his own designs (the ZIG ZAG and Ring Trigger pistols), patented a newly designed loading lever that lengthened the "web" and added a slot that permitted the cylinder to be removed without dropping the lever. These Remington-Elliot revolvers are the 1861 models. The frame was changed slightly to accomodate the new loading lever, but there were still no safety notches and the barrel threads were still shrouded on the early examples. The barrel stamp read "Patented Dec. 17, 1861 Manufactured by Remington's Ilion, N.Y."
After the pistols were in the field for a while, complaints started arriving at Remington concerning loose cylinders (the cylinder pin would start creeping into the slot with heavy use), the hammer spur (too long for small hands) and the lack of any safety device. Remington addressed these problems by removing the slot from the loading lever, lowering the hammer spur and adding the now familiar notches to the cylinder. In addition, to ease manufacture, a relief was cut into the frame that exposed the barrel threads, and the front sight was changed to a screw-in post with a pinched blade. Also, it appears that some of them, at least, had a slightly longer grip than the early models.
These changes were introduced gradually to the 1861 Army and Navy models until the design became a new model in it's own right, though Until frame inventory was depleted, the "New Model" revolvers continued to carry the 1861 patent date. These are known as the "Transition" pistols. The "New Model" revolvers were officially released in 1863, with the barrel markings reverting back to the 1858 patent date, reading: "PATENTED SEPT. 14. 1858 E. REMINGTON & SONS. ILION. NEWYORK. U.S.A NEW-MODEL", reflecting Remington's purchase of Beal's patent.
So, there you have it. Anyone who knows more about this than I do is encouraged to correct me, as I am as anxious as the next fellow to understand the convoluted story behind these marvelous revolvers.
Al